Softened rubber



Patented July 2, 194G t SOFTENED RUBBER Warren F. Busse, Akron, and Edward N. Cunningham, Cuyahoga Falls, Ohio, assignors to The B. F. Goodrich Company, New-York, N. Y., a H i corporation of New York No Drawing. Application October 11, 1938, Serial No. 234,484

6 Claims. (01. 260-761) This invention relates to the softening of rubhand, if the latex is to be worked up immediately bar or to increasing its plasticity, and has as its into solid rubber, either crude or compounded, object the preparation of a soft and plastic rubsuch a salt may function as a coagulant in adber directly from latex. dition to its primary function of softening the We have found that rubber may be softened rubber. The latex is also mixed with a substanand a highly plastic rubber may be prepared by tially neutral per-oxygen compound, meaning a treating latex with certain hydrazine compounds, compound containing loosely bound oxygen capreferably in the presence of certain oxygen pable of splitting off and oxidizing organic matecarriers. After heating or after the lapse of suflirials, such as y gen peroxide, per-salts such 10 cient time, the rubber will be found to be quite as s um p ate, p tassium p man a at 10 plastic and easily worked. The mastication Sodium chlorate, sodium perchlorate, ammonium which is ordinarily required before the rubber persuifate, potassium chromate, Potassium e Secan be used, with its attendant heavy machinery n t i m yp hl ri potassium p r rbonand great expenditure of energy, can be entirely t S m e, a d t l e, d Organic or partially tt peroxides such as acetyl peroxide, benzoyl per- 15 The compounds with which the latex is treated Oxide, succihyi p e, and t e like- S y in this invention are those in which at least the alkaline peroxides uch as NazOz or BaOz 'tend two hydrogens on one nitrogen remain unsubstito stiffen the rubber rather than to soften it. tuted, The class of cqmpounds which may be The latex may be heated if desired to accelerate employed accordingly includes the parent comfurther the softening o the rubber. pound, hydrazine, as well as derivatives in which AS Specific eXample of One embodiment of one or two hydrocarbon radicals, or radicals the invention, one part by Weigh of p y which have essentially the properties of hydrohydrazine hydrochloride is dissolved in 10 parts carbon radicals, such as ethyl, butyl, cyclohexy], of concentrated aqueous ammonia-and the solu-- benzyl, phenyl, tolyl, xylyl, cumyl, xenyl, naphtion is Slowly added to 100 pa s of apP -g thyl, anthracyl, indanyl, chlorphenyl, nitrophenmately 60% concentrated latex. To one portion yl, alkoxy-phenyl, furyl, quinolyl and the like, of this treated latex y Vol e 0f hyoccupy positions on a single one of the two nitrodrcgen per de is a ed After Standing o a gens Compounds in which th b tit t radiday the latex was dried to recover its rubber. cals are not substantially hydrocarbon in nature, The rubber f the latex Containing both the 30 such as radicals which are strongly acidic or phehylhydrazihe d the Peroxide Was quite basic or which contain carbonyl groups, are suby, t and p a d that Containing y stantially inactive and are excluded from this e p y ydrazine was somewhat tacky and class ofcompounds. The preferred compounds more plastic than rubber from untreated latex, are mono-aromatic substituted hydrazines such but not nearly as soft as that treated with both 5 as phenylhydrazine and beta-naphthyl hydrazine. Chemicals- Latex treated With hydrogen D The free bases may be used, or it may be more ide alone, on the other hand, was not noticeably convenient to add the compounds in the form of affected, the rubber being tough, resilient, and their salts with organic or inorganic acids or Praetieely a y. their molecular addition compounds with other The latex may be treated as soon as it is 001- 40 materials such as zinc acetate, phenol, S02, etc., lected, or at any later time, and maybe emit being understood that the claims, unless otherployed for any purpose for which a ft tacky Wise limited, cover the use of the compounds rubber is desired, as an adhesive, as an imeither free or in the form of salts or addition pregnating or coating medium for fibrous mate complexes rials and the like or ma be Worked u in 45 In practicing this invention one or more of the solid rubber either in its final shape or in tli hydrazines of the class set forth above is added to the latex in small proportion, say from 0.01% form of Crude rubber elttler unmedlaitely after to 1% or more of the rubber content of the latex, treatmint at deslred later tlme- The preferably as solutions or suspensions in water. proportlon of hydrazme Compound added and the If a salt of a hydrazine with a Strong acid is length of time between the treatment and the employed, t Should ordinarily be mixed t final use of the latex or the rubber derived theresufilcient ammonia or other base to render it neufrom Will be chosen in accordance With the D tral or. slightly alkaline to obviate any undesired ticular degree of so tne e If at y time tendency to coagulate the latex. On the other a lot of latex or rubber is permitted to become hydrazine in which at least the two hydrogensi, 1

on one nitrogen remain unsubstituted, and in which all substituents are hydrocarbon radicals, in the presence of a substantially neutral peroxygen compound.

2. The process of producing a softened rubber which comprises treating rubber latex with a hydrazine in which at least the two hydrogens on one nitrogen remain unsubstituted, and in which'all substituents are hydrocarbon radicals, in the presence of hydrogen peroxide.

3. The process of producing a softened rubber which comprises treating rubber latex with a mono-aryl substituted hydrazine in the presence of hydrogen peroxide.

4. The process of producing a softened rubber which comprises, treating rubber latex with phenylhydrazine in the presence of hydrogen peroxide.

5. The process of producing a softened rubber which comprises treating rubber latex with a mono-aryl substituted hydrazine in the presence of a substantially neutral per-oxygen compound.

6. The process'of producing a softened rubber which comprises treating rubber latex with phenyl hydrazine in the presence of a substantially neutral per-oxygen compound.

WARREN F. BUSSE. EDWARD N. CUNNINGHAM. 

